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Sucupira MVF, Argondizzo APC, Miguez M, de Araujo AEV, Silva LBR, Mello MB, Marques CFS, Brito E Cunha DRA, Bastos RC, de Paula VS, Amado Leon LA. Approaches to produce and characterize recombinant protein VP1-2A of HAV for serological rapid test application. J Virol Methods 2024; 323:114839. [PMID: 37923063 DOI: 10.1016/j.jviromet.2023.114839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 10/26/2023] [Accepted: 10/29/2023] [Indexed: 11/07/2023]
Abstract
Studies reporting the expression of hepatitis A virus (HAV) structural proteins, specifically recombinant VP1-2A containing an immunogenic activity, use the Escherichia coli system. Recombinant HAV proteins may represent a source of less expensive antigens for application in different diagnostic platforms. However, the formation of insoluble aggregates is an obstacle to obtaining large amounts of HAV proteins in their native form. To overcome this obstacle, some approaches were applied in this study to improve purification, solubility, and protein expression levels. Critical properties were evaluated. The introduction of another insertion codon to increase the protein concentration and vector activity was observed and verified by SDS-PAGE. The expression was established with 0.4 mM IPTG for 4 h at 37 °C. The VP1 protein was partially soluble at an isoeletric point (pI) of 6.45. The majority of HAV VP1-2A proteins measured 45.19 kDa in size and had a homogeneity of 53.58%. Multi-antigen print immunoassay (MAPIA) showed antigenicity at different HAV VP1-2A concentrations, and microsphere-based immunoassays showed a specificity of 100% and a sensitivity of 84%. HAV VP1-2A was characterized using different sensitivity methods to prove its biological activity, indicating its use as a tool for the diagnosis of Hepatitis A virus infection.
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Affiliation(s)
- Michel V F Sucupira
- Diagnostic Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil; Technological Development in Virology Laboratory, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Ana P C Argondizzo
- Recombinant Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Mariana Miguez
- Recombinant Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Anna E V de Araujo
- Recombinant Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Leila B R Silva
- Diagnostic Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Marcelle B Mello
- Diagnostic Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Christiane F S Marques
- Diagnostic Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Danielle R A Brito E Cunha
- Immunological Technology Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Renata C Bastos
- Macromolecules Laboratory, Immunobiological Technology Institute (Bio-Manguinhos), Fiocruz, Rio de Janeiro, Brazil
| | - Vanessa S de Paula
- Molecular Virology and Parasitology Laboratory, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil
| | - Luciane A Amado Leon
- Technological Development in Virology Laboratory, Oswaldo Cruz Institute, Fiocruz, Rio de Janeiro, Brazil.
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da Silva Junior HC, da Silva ED, Lewis-Ximenez de Souza Rodrigues LL, Medeiros MA. Recombinant VP1 protein as a potential marker for the diagnosis of acute hepatitis A virus infection. J Virol Methods 2017; 245:1-4. [DOI: 10.1016/j.jviromet.2017.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 01/02/2017] [Accepted: 03/07/2017] [Indexed: 12/21/2022]
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Silva HCD, Pestana CP, Galler R, Medeiros MA. Solubility as a limiting factor for expression of hepatitis A virus proteins in insect cell-baculovirus system. Mem Inst Oswaldo Cruz 2016; 111:535-8. [PMID: 27581123 PMCID: PMC4981117 DOI: 10.1590/0074-02760160153] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Accepted: 06/22/2016] [Indexed: 11/21/2022] Open
Abstract
The use of recombinant proteins may represent an alternative model to inactivated vaccines against hepatitis A virus (HAV). The present study aimed to express the VP1 protein of HAV in baculovirus expression vector system (BEVS). The VP1 was expressed intracellularly with molecular mass of 35 kDa. The VP1 was detected both in the soluble fraction and in the insoluble fraction of the lysate. The extracellular expression of VP1 was also attempted, but the protein remained inside the cell. To verify if hydrophobic characteristics would also be present in the HAV structural polyprotein, the expression of P1-2A protein was evaluated. The P1-2A polyprotein remained insoluble in the cellular extract, even in the early infection stages. These results suggest that HAV structural proteins are prone to form insoluble aggregates. The low solubility represents a drawback for production of large amounts of HAV proteins in BEVS.
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Affiliation(s)
- Haroldo Cid da Silva
- Fundação Oswaldo Cruz, Instituto de Tecnologia em Imunobiológicos, Laboratório de Tecnologia Recombinante, Rio de Janeiro, RJ, Brasil
| | - Cristiane Pinheiro Pestana
- Fundação Oswaldo Cruz, Instituto de Tecnologia em Imunobiológicos, Laboratório de Tecnologia Recombinante, Rio de Janeiro, RJ, Brasil
| | - Ricardo Galler
- Fundação Oswaldo Cruz, Instituto de Tecnologia em Imunobiológicos, Laboratório de Tecnologia Recombinante, Rio de Janeiro, RJ, Brasil
| | - Marco Alberto Medeiros
- Fundação Oswaldo Cruz, Instituto de Tecnologia em Imunobiológicos, Laboratório de Tecnologia Recombinante, Rio de Janeiro, RJ, Brasil
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Specht E, Miyake-Stoner S, Mayfield S. Micro-algae come of age as a platform for recombinant protein production. Biotechnol Lett 2010; 32:1373-83. [PMID: 20556634 PMCID: PMC2941057 DOI: 10.1007/s10529-010-0326-5] [Citation(s) in RCA: 163] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 06/07/2010] [Indexed: 12/03/2022]
Abstract
A complete set of genetic tools is still being developed for the micro-alga Chlamydomonas reinhardtii. Yet even with this incomplete set, this photosynthetic single-celled plant has demonstrated significant promise as a platform for recombinant protein expression. In recent years, techniques have been developed that allow for robust expression of genes from both the nuclear and plastid genome. With these advances, many research groups have examined the pliability of this and other micro-algae as biological machines capable of producing recombinant peptides and proteins. This review describes recent successes in recombinant protein production in Chlamydomonas, including production of complex mammalian therapeutic proteins and monoclonal antibodies at levels sufficient for production at economic parity with existing production platforms. These advances have also shed light on the details of algal protein production at the molecular level, and provide insight into the next steps for optimizing micro-algae as a useful platform for the production of therapeutic and industrially relevant recombinant proteins.
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Affiliation(s)
- Elizabeth Specht
- San Diego Center for Algae Biotechnology, Department of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0368 USA
| | - Shigeki Miyake-Stoner
- San Diego Center for Algae Biotechnology, Department of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0368 USA
| | - Stephen Mayfield
- San Diego Center for Algae Biotechnology, Department of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0368 USA
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Specht E, Miyake-Stoner S, Mayfield S. Micro-algae come of age as a platform for recombinant protein production. Biotechnol Lett 2010; 32:1373-1383. [PMID: 20556634 DOI: 10.1007/s10529-010-0326-325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Accepted: 06/07/2010] [Indexed: 05/28/2023]
Abstract
A complete set of genetic tools is still being developed for the micro-alga Chlamydomonas reinhardtii. Yet even with this incomplete set, this photosynthetic single-celled plant has demonstrated significant promise as a platform for recombinant protein expression. In recent years, techniques have been developed that allow for robust expression of genes from both the nuclear and plastid genome. With these advances, many research groups have examined the pliability of this and other micro-algae as biological machines capable of producing recombinant peptides and proteins. This review describes recent successes in recombinant protein production in Chlamydomonas, including production of complex mammalian therapeutic proteins and monoclonal antibodies at levels sufficient for production at economic parity with existing production platforms. These advances have also shed light on the details of algal protein production at the molecular level, and provide insight into the next steps for optimizing micro-algae as a useful platform for the production of therapeutic and industrially relevant recombinant proteins.
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Affiliation(s)
- Elizabeth Specht
- San Diego Center for Algae Biotechnology, Department of Biological Sciences, University of California, San Diego, 9500 Gilman Dr., La Jolla, CA 92093-0368, USA
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Baptista ML, Silva M, Lima MAD, Yoshida CF, Gaspar AMC, Galler R. Genetic variability of hepatitis A virus strain HAF-203 isolated in Brazil and expression of the VP1 gene in Escherichia coli. Mem Inst Oswaldo Cruz 2007; 101:759-66. [PMID: 17160284 DOI: 10.1590/s0074-02762006000700009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 07/31/2006] [Indexed: 11/22/2022] Open
Abstract
The hepatitis A virus (HAV) HAF-203 strain was isolated from an acute case of HAV infection. The primary isolation of HAF-203 in Brazil and its adaptation to the FRhK-4 cell lineage allowed the production of large amounts of viral particles enabling molecular characterization of the first HAV isolate in Brazil. The aim of our study was to determine the nucleotide sequence of the HAF-203 strain genome, compare it to other HAV genomes and highlight its genetic variability. The complete nucleotide sequence of the HAF-203 strain (7472 nucleotides) was compared to those obtained earlier by others for other HAV isolates. These analyses revealed 19 HAF-specific nucleotide sequence differences with 10 amino acid substitutions. Most of the non-conservative changes were located at VP1, 2C, and 3D genes, but the 3B region was the most variable. The availability of HAF-203 complementary DNA was useful for the production of the recombinant VP1 protein, which is a major determinant of viral infectivity. This recombinant protein was shown by enzyme-linked immunoassay and blotting, to be immunogenic and resemble the native protein, therefore suggesting its value as a reagent for incorporation into diagnostic tests.
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Affiliation(s)
- Marcia L Baptista
- Laboratório de Hepatites Virais, Departamento de Virologia, Instituto Oswaldo Cruz-Fiocruz, Av. Brasil 4365, 21040-900 Rio de Janeiro, RJ, Brazil.
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Schmidtke P, Habermehl P, Knuf M, Meyer CU, Sänger R, Zepp F. Cell mediated and antibody immune response to inactivated hepatitis A vaccine. Vaccine 2006; 23:5127-32. [PMID: 16054733 DOI: 10.1016/j.vaccine.2005.06.022] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2004] [Revised: 06/21/2005] [Accepted: 06/23/2005] [Indexed: 11/30/2022]
Abstract
The humoral and cellular immune response to inactivated hepatitis A vaccine was investigated dynamically in a time elapse study over 1 year. Fourty-five healthy volunteers, seronegative for anti-HAV, were vaccinated with 1440 enzyme-linked immunosorbent assay units (EU) of formalin-inactivated hepatitis A virus following a 0--6-month schedule. Serum anti-HAV levels and HAV-specific proliferation of peripheral blood mononuclear cells were measured at several time points over a 26- and 28-week period after the first and second injection, respectively. Distinct B and T cell responses were determined within 14 days after primary vaccination. The booster vaccination-induced immediate peak levels for the humoral (anti-HAV GMC=5376mIU/ml) as well as the cellular (median Deltacpm=14173cpm) response.
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Affiliation(s)
- P Schmidtke
- Pediatric Immunology and Infectious Diseases, Children's Hospital, University of Mainz, Obere Zahlbacher Str.63, DMG, 55131 Mainz, Germany.
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Cederna JB, Klinzman D, Stapleton JT. Hepatitis A virus-specific humoral and cellular immune responses following immunization with a formalin-inactivated hepatitis A vaccine. Vaccine 1999; 18:892-8. [PMID: 10580203 DOI: 10.1016/s0264-410x(99)00342-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To evaluate proliferative T cell responses elicited by a formalin-inactivated HAV vaccine, we immunized 10 subjects with an inactivated HAV vaccine, and measured HAV antibody titers and HAV-specific T cell proliferation. gamma-Interferon production by PBMC's was evaluated in selected subjects. By week 30, seroconversion (geometric mean titer=2299 mIU/ml), and HAV-specific proliferation was detected in all subjects. HAV also induced gamma-interferon in the three subjects studied. These data indicate that the inactivated HAV vaccine induces proliferative T cell responses in addition to HAV antibody. This may be important for protection against hepatitis A, and suggests that recall memory for HAV antigen is elicited by the vaccine.
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Affiliation(s)
- J B Cederna
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City, IA 52242, USA
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LaBrecque FD, LaBrecque DR, Klinzman D, Perlman S, Cederna JB, Winokur PL, Han JQ, Stapleton JT. Recombinant hepatitis A virus antigen: improved production and utility in diagnostic immunoassays. J Clin Microbiol 1998; 36:2014-8. [PMID: 9650953 PMCID: PMC104969 DOI: 10.1128/jcm.36.7.2014-2018.1998] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/1997] [Accepted: 03/17/1998] [Indexed: 02/08/2023] Open
Abstract
Hepatitis A virus (HAV) immunoassays use cell culture-derived HAV antigen to detect HAV-specific antibodies. The current method of production of HAV antigen in tissue culture is time-consuming and expensive. We previously expressed the HAV open reading frame in recombinant vaccinia viruses (rV-ORF). The recombinant HAV polyprotein was accurately processed and was assembled into subviral particles. These particles were bound by HAV-neutralizing antibodies and were able to elicit antibodies which were detected by commercial immunoassays. The present investigation compared the production of HAV antigen by standard tissue culture methods to the production of HAV antigen with the recombinant vaccinia virus system. In addition, HAV and rV-ORF antigens were assessed for their utility in diagnostic immunoassays. Serum or plasma samples from HAV antibody-positive and antibody-negative individuals were evaluated by immunoassay that used either HAV or rV-ORF antigen. All samples (86 of 86) in which HAV antibody was detected by a commercial enzyme-linked immunosorbent assay (ELISA) also tested positive by the recombinant antigen-based immunoassay (VacRIA). Similarly, all samples (50 of 50) that were HAV antibody negative also tested negative by the VacRIA. The lower limit of detection of HAV antibody was similar among immunoassays with either HAV or rV-ORF antigen. Thus, in the population studied, the sensitivity and specificity of the VacRIA were equivalent to those of the commercial ELISA. Since production of recombinant antigen is faster and less expensive than production of traditional HAV antigen, the development of diagnostic HAV antibody tests with recombinant HAV antigen appears warranted.
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Affiliation(s)
- F D LaBrecque
- Department of Internal Medicine, Iowa City Veterans Affairs Medical Center and The University of Iowa, 52242, USA
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Karayiannis P, O'Rourke S, Watts R, Waters J, Hill V, Carman WF, Thomas HC. Recombinant vaccinia viruses expressing hepatitis A virus structural polypeptides: detection of an anti-VP0 response in convalescent-phase sera. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1995; 2:708-11. [PMID: 8574835 PMCID: PMC170226 DOI: 10.1128/cdli.2.6.708-711.1995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have generated a number of recombinant vaccinia viruses which expressed the hepatitis A virus (HAV) structural polypeptides VP1, VP2, VP3, and VP4, either alone or in combination. The relevant sequences encoding these polypeptides were amplified from cloned cDNA by PCR and then cloned into the insertion vector pGS62. The presence of the HAV structural polypeptide-encoding sequences in the recombinant viruses was confirmed by Southern blot analysis, whilst their transcription and translation were demonstrated by Northern (RNA) blot analysis and immunodetection, respectively. Immunoprecipitation studies using these constructs have detected the presence of an anti-VP0 response in human convalescent sera following HAV infection. The significance of this finding and the usefulness of these constructs in studying cell-mediated immunity during recovery from HAV infection are discussed.
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Affiliation(s)
- P Karayiannis
- Department of Medicine, St. Mary's Hospital Medical School, Imperial College of Science, Technology and Medicine, London, United Kingdom.
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Ivanov VS, Kulik LN, Gabrielian AE, Tchikin LD, Kozhich AT, Ivanov VT. Synthetic peptides in the determination of hepatitis A virus T-cell epitopes. FEBS Lett 1994; 345:159-61. [PMID: 7515358 DOI: 10.1016/0014-5793(94)00427-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Computer search for probable T-epitopes of hepatitis A virus capsid proteins was performed using an integrated set of programs. Eight segments of the VP1, VP2, VP3 and VP4 proteins were chosen and synthesised. Five peptides previously examined as probable B-epitopes were used as well. All the peptides were tested for their ability to stimulate proliferation of lymph node T-cells primed with synthetic peptides. Almost all predicted T-epitopes affected the T-cell proliferation. None of the peptides had mitogenic activity. We demonstrated that regions 17-33 and 276-298 of VP1 are possible immunodominant promiscuous sites activating lymphocytes of all mouse haplotypes.
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Affiliation(s)
- V S Ivanov
- Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow
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12
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Lemon SM. Hepatitis A virus: Current concepts of the molecular virology, immunobiology and approaches to vaccine development. Rev Med Virol 1992. [DOI: 10.1002/rmv.1980020204] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Tesar M, Harmon SA, Summers DF, Ehrenfeld E. Hepatitis A virus polyprotein synthesis initiates from two alternative AUG codons. Virology 1992; 186:609-18. [PMID: 1310188 DOI: 10.1016/0042-6822(92)90027-m] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The genomic RNA of hepatitis A virus has two potential translation initiation sites for synthesis of a 251-kDa polyprotein. It is not known which of these AUG codons, located at positions 735-737 and 741-743, is used in vitro or in vivo. Site-directed mutagenesis was carried out to eliminate each start codon independently. Transcripts from the unmodified and modified cDNA clones were used either to program an in vitro translation system or for transfection of BS-C-1 cells. In vitro and in vivo translation data revealed preferential usage of the downstream AUG located at position 741 to 743, although either site could be utilized in the absence of the other. Both modified RNAs were able to induce productive infections in BS-C-1 cells. Deletion of almost all of the 5'-untranslated region (5'UTR) of the RNA, however, stimulated selection of AUG 735-737 in vitro resulting in equal utilization of both sites, suggesting a strong influence of the 5'UTR for directing the ribosome to a specific internal initiation site.
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Affiliation(s)
- M Tesar
- Department of Cellular, Viral, and Molecular Biology, University of Utah School of Medicine, Salt Lake City 84132
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Abstract
More than a decade ago, successful replication of hepatitis A virus (HAV) in cell culture opened the way to the development of live attenuated and inactivated vaccine candidates. Serial passages of HAV in cell culture led to attenuation as demonstrated by experiments in non-human primates. Several live vaccine candidates obtained through serial passages have been evaluated in volunteers. Significant improvements in the yield of viral antigen from infected cell cultures stimulated the development of killed vaccine candidates. These formalin-inactivated vaccines contain the viral capsid antigens assembled into viral particles. The immunogenic potential of the vaccine candidates depends strongly on the preservation of the configuration of the capsid proteins. Synthetic peptides covering immunogenic sequences of VP1 as well as soluble capsid proteins expressed as fusion proteins in Escherichia coli were therefore only weakly immunogenic when injected at high concentrations in rabbits. On the other hand, tamarin monkeys immunized with a live recombinant vaccinia expressing P1 were protected against virulent challenge. There are, however, considerable drawbacks related to the use of live vaccinia as a carrier virus. Chimeric polio-HAV VP1 viruses have been constructed. These hybrid viruses were not able to induce an immune response, probably because of configurational constraints of poliovirus on the inserted HAV epitopes. More recently, encouraging data on empty virus particles expressed in baculovirus and vaccinia virus systems have been reported.
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Affiliation(s)
- E D'Hondt
- SmithKline Beecham Biologicals, Rixensart, Belgium
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Abstract
Hepatitis A virus (HAV) is distinguished from other picornaviruses by its tropism for the liver in infected hosts, a nonlytic infection in hepatocytes, and a slow and nonlytic growth cycle in cultured cells. Although the genome structure and organization of HAV appear to be similar to those of the other picornaviruses, the viral proteins synthesized in infected cells have not been previously characterized. We have utilized specific antisera raised in rabbits to recombinant HAV proteins expressed in Escherichia coli in an effort to identify both structural and nonstructural proteins in BS-C-1 cells throughout the course of a viral replication cycle. Replication was monitored by dot blot hybridization of viral genomes. Structural proteins VP0, VP1, VP2, and VP3 were found to accumulate during the infection cycle as did viral RNA. Nonstructural proteins 2C and 3D were not detected on immunoblots, although a minor amount of 2C could be detected by immunoprecipitation of lysates of radiolabeled, infected cells. The relative sensitivities of the various antisera were determined, and the failure to observe nonstructural proteins was shown not to be due to decreased sensitivity of the detection reagents. Thus, it appears that HAV nonstructural proteins do not accumulate in infected cells to levels comparable to those of capsid proteins.
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Affiliation(s)
- W S Updike
- Department of Cellular, Viral, and Molecular Biology, University of Utah School of Medicine, Salt Lake City 84132
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Winokur PL, McLinden JH, Stapleton JT. The hepatitis A virus polyprotein expressed by a recombinant vaccinia virus undergoes proteolytic processing and assembly into viruslike particles. J Virol 1991; 65:5029-36. [PMID: 1651421 PMCID: PMC248966 DOI: 10.1128/jvi.65.9.5029-5036.1991] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Hepatitis A virus (HAV) contains a single-stranded, plus-sense RNA genome with a single long open reading frame encoding a polyprotein of approximately 250 kDa. Viral structural proteins are generated by posttranslational proteolytic processing of this polyprotein. We constructed recombinant vaccinia viruses which expressed the HAV polyprotein (rV-ORF) and the P1 structural region (rV-P1). rV-ORF-infected cell lysates demonstrated that the polyprotein was cleaved into immunoreactive 29- and 33-kDa proteins which comigrated with HAV capsid proteins VP0 and VP1. The rV-P1 construct produced a 90-kDa protein which showed no evidence of posttranslational processing. Solid-phase radioimmunoassays with human polyclonal anti-HAV sera and with murine or human neutralizing monoclonal anti-HAV antibodies recognized the rV-ORF-infected cell lysates. Sucrose density gradients of rV-ORF-infected cell lysates contained peaks of HAV antigen with sedimentation coefficients of approximately 70S and 15S, similar to those of HAV empty capsids and pentamers. Immune electron microscopy also demonstrated the presence of viruslike particles in rV-ORF-infected cell lysates. Thus, the HAV polyprotein expressed by a recombinant vaccinia virus demonstrated posttranslational processing into mature capsid proteins which assembled into antigenic viruslike particles.
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Affiliation(s)
- P L Winokur
- Department of Internal Medicine, University of Iowa College of Medicine, Iowa City
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